Since their conception and design, portable personal computers, as with all computers, have faced the issue of thermal management as a result of heat generated by the processor and other components of the computer. As is well known, excessive heat can degrade performance of computers and result in damage to components of computers. As a result, thermal management is often an important consideration in computer design.
In the last few years, thermal dissipation requirements of portable computers have increased. For example typical portable computers generate heat that must be dissipated in the range of from about 10 watts to about 20 watts and beyond. This is at least in part a result of ever increasing CPU performance. For example, see Yu, THE FUTURE OF MICROPROCESSORS, IEEE Micro, December 1996, pp. 46-53, the entire contents of which are hereby incorporated by reference. Additional heat is also generated by increasing functions performed by portable personal computers, such as digital video disk (DVD), modem, audio, video, among other devices, now often included in portable personal computers. It is expected that future portable personal computers will provide even greater processing performance and functions, thereby continuing the trend of increasing heat dissipation.
For example, with an A4 form factor, i.e., with a 297 mm by 210 mm footprint, the cooling limit for a PC without fan is from about 15 to about 20 watts. Providing more cooling than these limits can not only be a competitive advantage, but also a product differentiation.